…biofuel crops demand vast amounts of land to produce quite limited energy yield. he notes that once upon a time the human race generated nearly all its energy from biomass fuel, but that only worked with a Middle Ages living-standard and population.

One of the things that annoys me about the global warming/renewable energy/hydrodgen economy arguments are that some attractive arguments aren’t terribly well grounded in numbers, the sort of numbers that tell us what would need to happen to make a significant difference at our current rate of energy consumption.

I’ve never been convinced that crop based biofuels are a good idea from a net energy perspective, and I’m really not convinced about hydrogen as a power source, unless there’s fission or fusion involved. Biofuels are great for turning a waste stream into usable fuel, but it doesn’t scale. There’s just not that much waste product to make a dent in the oil stream.